This column will change your life: The worst that could happen? Bring it on, says Oliver Burkeman

The ancient Romans and Greeks made no distinction between philosophy, therapy and self-help. "Philosophy's power to blunt the blows of circumstance is beyond belief," observed Seneca the Stoic; the very aim of philosophy, he argued, was "the state of happiness". Today, with philosophers confined to academia, we've come to think of therapy as being for troubled people and self-help for slightly flaky people - as if minimising sad emotions and maximising happy ones wasn't the most universal of all challenges. It's hard to imagine what Seneca might have felt about a world in which philosophers don't seek happiness, and those seeking happiness read Deepak Chopra. Or, rather, it isn't: he'd have been stoical about it, one assumes. But you take my point.

I've enthused here before about another Stoic, Epictetus, and his insight that emotions are responses not to reality but to thoughts about reality - a perspective now deeply embedded in approaches both wise (cognitive therapy) and unwise (The Secret). But Seneca's Letters From A Stoic goes further. Essentially, it's a training manual for answering - really answering - one question: What's the worst that could happen? The author Tim Ferriss, a Seneca fan, calls this "negative visualisation": responding to anxiety, for example, not by trying to persuade oneself that all will be well, but by fleshing out, in detail, the worst-case scenario.

This works partly because rendering fears specific, rather than nebulous, will always make them more manageable. But it also works simply by drawing attention to the fact that fearful thoughts about the future are just that: thoughts. And it doesn't only apply to fear, but also to the unhappiness that comes from not having what you want. Since it isn't external reality that determines emotions, Seneca might say, you're wrong to imagine that the perfect relationship, job or house would make you happy. What's making you unhappy is the belief that you need them in order to be happy. The way to be happy is to drop that thought.

This can sound like a recipe for withdrawal from the world, and it doesn't help that Seneca did, in fact, spend much of his life in seclusion. If things "out there" don't bring happiness, and if any crappy circumstance can be made tolerable by mental training, why seek love, nurture friendships, strive for achievements, fight injustice or create art? Why not just extinguish your appetite for that stuff instead?

This is how some people interpret Buddhism, too. But extinguishing desires and fears doesn't work - which, presumably, is why a fair proportion of people one meets who proudly declare they've become Buddhists seem so tightly wound.

But that's not what Seneca meant, and not, as far as I can discern, what Buddhists mean, either. Stoicism can be just as easily seen as a way to participate more fully in the world, to plunge in more deeply precisely because one has sapped it of any absolute power to dictate one's emotional state. In Buddhist terms, it's the subtle difference between detachment and non-attachment. "Detachment implies a sense of withdrawal," the meditation teacher Joseph Goldstein says in an interview on the philosophy/spirituality website meaningoflife.tv. (And if you've never visited that fascinating site, please don't, unless you've got nothing pressing to do for the next month or so.) "Non-attachment simply implies not holding on."